The zombie film is ripe for comedy -- how could it not be? All those shambling, moaning corpses, drooling vacantly as they pursue living flesh, then slurping intestines with a gourmand's brio.

The genre's modern-day innovator George Romero understood its inherent farcical qualities perfectly well; in his seminal Night of the Living Dead, we find a guy on TV summing up the zombie epidemic with "Ah, they're dead -- they're all messed up," and in 1979's Dawn of the Dead more than a few walking dead literally catch pies in the kisser. Even in a grim rip-off like Lucio Fulci's Zombie there's the well-loved underwater face-off between a zombie and a shark (guess who wins).

Edgar Wright (director and co-writer) and Simon Pegg (co-writer and star) understand just as well, and the film they have wrought, Shaun of the Dead (already a big hit in Britain), is not only a loving, teasing homage to the Romero Dead films. It's also a superb zombie film in its own right, its humor always grounded in character reality and those characters' plausible reactions to extraordinary circumstances. Wright and Pegg, like John Landis in An American Werewolf in London, first give us funny, recognizable human beings, and then let loose the wolves and flesh-eaters. Horror fans will devour it whole, but the squeamish or easily-spooked shouldn't avoid it; it's also a superb comedy in its own right.

The eponymous Shaun (Pegg) lives in a cluttered London flat with childhood buddy turned slacker roomie Ed (Nick Frost, hilarious even when his sometimes-thick accent baffles American ears). Shaun toils in an appliance store; at age 29 he's settled for whatever life hands him, as long as he can go to his favorite pub at the end of the day and get sloshed with Ed. His girlfriend Liz (Kate Ashfield) is sick of waiting for him to grow up. For about the first reel, Shaun deals with the various mundane aggravations of his life, with odd things always happening in the backgrounds of shots. That Shaun and his self-absorbed friends -- including aspiring actress Dianne (Lucy Davis) and her wimpola boyfriend David (Dylan Moran) -- would ignore the growing evidence of the undead is perfectly credible. "Panic on the streets of London," sings Morrissey on the telly in one scene. Well, not quite yet.

Soon enough the infection spreads, literally into Shaun and Ed's back yard -- a forlorn zombie woman they take for a drunk. Other zombies quickly join her, and the two slackers decide on the ideal place for holing up -- not a shopping mall, but their favorite pub. Along for the ride are Liz, Dianne, David, and Shaun's sweetly oblivious mum (Penelope Wilton, the best mom in horror movies since Mimi Rogers in Ginger Snaps). What follows hews closer to gut-wrench than to belly-laugh, though our heroes remain riotous in their consistency; when the power comes back on, and everyone is straining to keep quiet to hide from the zombies outside, Ed does something spectacularly stupid yet absolutely in character. The writing is so sharp that nothing anyone does rings false, even when a newly zombified character reaches out with a mottled claw to ... turn off an offending stereo.

I picture George Romero howling with glee at Shaun of the Dead (the American ads carry his enthusiastic blurb), maybe because the movie so successfully continues his legacy. Romero's films are uniquely American, and Shaun of the Dead is inconceivable anywhere but London, where survivors take stock of the situation over Guinness and crisps.

But the movie is far from a Mel Brooks-style lampoon; it takes the rules seriously (even when ribbing them) and isn't afraid to nudge the audience into true horror or even pathos when the story calls for either. In spirit, it's far closer to Romero's vision than last spring's dull 'Dawn of the Dead' remake. It knows when to play for laughs and when to play for keeps.